Trigger control switch with particular bridging and stationary contact arrangements

ABSTRACT

A switch in combination with a variable power control. A sliding actuator carries a bridging contact which continuously engages a pivot on one fixed contact and selectively engages two fixed contacts. An actuator pivot urges the bridging contact toward the fixed contacts, and the relative positions of the pivots provide positive switching between bridging and nonbridging conditions. An insulating boss separates the stationary fixed contacts, and the bridging contact never engages said boss in any switch position. A thick film circuit carries resistance elements on a surface; and a second movable contact, moved by the actuator, includes contact fingers engaging the resistance elements.

{54] TRIGGER CONTROL SWITCH WITH PARTICULAR BRIDGING AND STATIONARY 0United States Patent m1 3,629,534

[72] Inventor Benny L.Reviel 2,966,560 12/1960 Gluck 200/I6R Irving,Tex. 3,456,230 7/1969 Matthews et al 20/157 UX [2]] AppLNot 34,3453,536,973 l0/l970 Matthewsetal 200/l57X [22] Med May 1970 PrimaryExaminer-Robert K. Schaefer [45] Patented Dec.2l,l971 E R b A V d hAssignee ECC Comm-non ssislanl xarnmero ert an er ye Euless TexAttorneys-Giles C. Clegg, Jr. and Peter J. Murphy ABSTRACT: A switch incombination with a variable power control. A sliding actuator carries abridging contact which continuously engages a pivot on one fixed contactand selectively engages two fixed contacts. An actuator pivot urges thebridging contact toward the fixed contacts, and the relative positionsof the pivots provide positive switching between bridging andnonbridging conditions. An insulating boss separates the stationaryfixed contacts, and the bridging contact never engages said boss in anyswitch position. A thick film circuit carries resistance elements on asurface; and a second movable contact, moved by the actuator, includescontact fingers engaging the resistance elements.

PAIENTEU m2! an 3529534 sum 2 or 3 F'IC35 6 V I6 30 INVENTOR BENNY'L.REVIEL I3 fljwg g FIG. I I

ATTORNEY PATENTED 051221 197! 3629.534 SHEET 3 0F 3 I INVENTOR 4O 26 6957 27 BENNY L. REVIEL FIG.9

ATTORNEYS TRIGGER CONTROL SWITCH WITII PARTICULAR BRIDGING ANDSTATIONARY CONTACT ARRANGEMENTS BACKGROUND OF THE INVENTION Thisinvention relates to a positive acting switch operated by a slidingactuator, suitable for use to control the power to a manually heldelectric tool. This invention also relates to the combination of such aswitch with a variable power control for such an electrically operatedtool.

In tools of the above type, it is usual to provide a pistol griptypehandle with a trigger-type actuator engaged by the finger of the tooloperator to control the power to the tool. Initial movement of thetrigger will energize the motor at a low power level providing a lowspeed for the tool motor. Further squeezing movement by the operatorwill increase the power to increase the speed of the tool motor. Thetool motor, then, is switched on and off and the power to the motor isvaried in response to movement of a sliding actuator which carriescontacts coacting with fixed contacts to produce the desired control.

In this type of motor control, wherein the relatively moving parts whichcarry the electric contacts are fabricated on insulating material suchas plastic material, it is desirable to minimize rubbing engagement ofinsulating parts which, through abrasion, may produce insulatingparticles which may build up over a period of time to interfere with theoperation of the switch assembly or which may build up on the contactsurfaces to increase contact resistance.

It is an object of this invention to provide an electric switch suitablefor use in a variable power control in which positive switching actionis obtained.

Another object of this invention is to provide a switch actuated by asliding actuator in which positive snap action switching is obtained.

A further object of this invention is to provide a switch providing abridging contact carried by a sliding actuator in i which positiveswitching action is obtained through engagement only with the switchstationary contacts.

A still further object of this invention is to provide a positive actingswitch in combination with a thick film circuit having integralresistance elements for variable control.

These objects are accomplished in a switch assembly comprising astationary housing and an actuator mounted for rectilinear movementrelative to the stationary housing. At least two longitudinally spacedstationary contacts are mounted on the stationary housing, one contactincluding an integral pivot. An elongated bridging contact carried bythe actuator is urged into engagement with the stationary contacts, withthe bridging contact being pivoted into or out of engagement with theother stationary contact responsive to the position of the bridgingcontact relative to the pivot of the one contact. For variable powercontrol, an elongated resistor means is mounted on the stationaryhousing and connected to one of the fixed contacts. A sliding contact,movable with the actuator, selects relative resistance values of theresistor means.

DRAWINGS The novel features of the invention, as well as additionalobjects and advantages thereof, will be understood more fully from thefollowing description when read in connection with the accompanyingdrawings in which:

FIG. I is a view, partially in section, of a preferred form of switchassembly, as viewed from one side of the assembly;

FIG. 2 is a view similar to FIG. I as viewed from the opposite side ofthe switch assembly;

FIGS. 3 and 5 are fragmentary views based on FIG. 1 illustratingdifferent operative positions of the switch elements;

FIGS. 4 and 6 are fragmentary views based on FIG. 2 illustratingoperative positions of the switch elements which correspond respectivelyto the operative positions illustrated in FIGS. 3 and 5 FIG. 7 is a viewof a thick film printed circuit employed in the switch assembly of FIG.I; FIG. 8 is a sectional view taken along the Line 8-8 of FIG.

FIG. 9 is a sectional view taken along the Line 99 of FIG. I;

FIG. 10 is a sectional view, as viewed along the Line I0 10 of FIG. 2,illustrating the relation of the thick film circuit to other elements ofthe assembly; and

FIG. 11 is a schematic circuit diagram of a power control circuit for anelectric motor.

DESCRIPTION OF THE PREFERRED EMBODIMENT The electric switch apparatusand power control circuit described herein are designed for use in amotor control circuit for varying the power supplied to an electricmotor of the type used in the portable tool, such as drill, for varyingthe speed of the tool.

FIG. 11 is a schematic diagram of an exemplary control circuit forcontrolling the effective power applied to a load, such as a motor 15,by varying the resistance of resistors in the control circuit and whichare not connected in series with the load. It will be appreciated inthis regard that there are many types of control circuits in which theeffective power applied to a load is varies by varying a variableresistor not connected in series with the load. The switch apparatus ofthe present invention can be used with such other circuits as theparticular control circuit does not constitute a part of the invention.

In the particular control circuit shown in FIG. II of the drawings,power is applied to the motor 15 when bridging contact 25 is connectedacross contacts 26 and 27 and when bridging contact 20 is connectedacross contacts 21 and 22. Upon this occurrence, the motor 15 isconnected in series with the symmetrical AC switch I3 across a source ofAC supply voltage connected to terminals 11 and I2. The effective powerapplied to the motor, and thereby the speed of motor, is controlled bycontrolling the conduction time of the device I3 during each half cycleof the applied AC supply voltage. The conduction time of the device 13is controlled by controlling the resistance of the charge path of thecapacitor 14, thereby controlling the time required for the capacitor 14to be charged to the breakover voltage of breakover diode 16. Thus, thecapacitor 14 is connected across the power device 13 by means includingresistors 33 and 34 connected in series with the capacitor 14 andcontacts 21 and 22, terminal 36 of resistor 34 being connected to switchcontact 22, and terminal 35 of resistor 33 being connected to oneterminal of a capacitor. As the sliding contact 30 is moved with itsspring contacts 31 and 32 moving along resistors 33 and 34 respectivelytoward terminals 35 and 36 respectively, the resistance in the chargepath of the capacitor 14 will be decreased causing the capacitor tocharge to the breakover voltage of the device 16 at a faster rate.Accordingly, the power device 13 will be switched to the low impedancestate at an earlier time in each half cycle, increasing the effectivepower applied to the load. At such time as sliding contacts 31 and 32approach the terminals 35 and 36, bridging contact 20 contacts contact23. On this occurrence, contact 21 will be connected directly to themotor 15 and full power will be applied to the motor.

The bridging contacts 20 and 25 and sliding contact 30 are commonlyactuated by a single control element which is biased to a position thatthe resistance between capacitor 14 and terminal 22 is maximum and theswitches are open isolating the motor from line voltage prior tooperation of the control element. Upon operation of the control element,both switches will be operated and the slider advanced to charge theresistance in the charge path of capacitor 14 to vary the power suppliedto the motor in accordance with the position of the control element. Asingle resistor rather than the two resistors 33 and 34 could be used.However, for a given resistance per unit length, a greater change inresistance for an incremental change in the distance the slider 30 ismoved will provide a greater change in resistance and provide a greaterchange in the speed of the motor 15.

Referring now to the other figures of the drawing and particularly toFIGS. 1, 2, 8 and 9, the switch assembly includes a generallyrectangular housing 40 which is adapted to be received and secured in anappropriate recess in the pistol grip handle of a portable power toolfor example. The housing 40 is open at the bottom, as viewed in FIG. 1,to receive a switch subassembly 41 which includes, generally, thestationary elements of the switch mechanism. An actuator 45 includes ahorizontal shank portion 46 which is slidably received and supported inthe upper portion of the housing 40, the shank portion 46 extending intothe housing through an opening 42 in the housing wall. The shank portion46 of the actuator carries the movable elements of the switchingmechanism, as will be described; and a trigger element 47 is provided atthe outer end of the actuator suitable for engagement by the finger of atool operator while gripping the piston grip handle of a portable tool.A compression spring 48 urges the actuator 45 to an outermost extendedposition, which is determined by coacting stop means (not shown)provided on the housing and actuator. The housing 40, actuator 45, andbase parts of the subassembly 41 are all preferably fabricated of anelectrically insulating material, such as a plastic material.

FIG. 9 is a top view of the switch subassembly 41, with the partscarried by the actuator 45 not shown for purposes of clarity. Thesubassembly 41 includes two blocks 51 and 52 which define horizontalsurfaces 53 and 54 respectively for supporting the several stationarycontacts, which define an upstanding rib 55, defining insulating andguiding walls between the surfaces 53 and 54, and which defines supportmeans for other circuit elements and components as will be described. Asbest seen in FIGS. 1 and 9, stationary contacts 26 and 27 are.supportedon the surface 53 on one side of the barrier 55. As best seen in FIGS. 2and 9, stationary contacts 21, 22 and 23 are supported on the surface 54on the opposite side of the barrier 55. The surface 53 is provided withan upwardly extending transverse rib 57 defining an insulating barrierbetween the longitudinally spaced contacts 26 and 27; andcorrespondingly the surface 54 is provided with an upwardly extendingtransverse rib 58 defining an insulating barrier between thelongitudinally spaced contacts 21 and 22.

As seen in the drawings, the blocks 51 and 52 define a subassembly whichis rectangular in configuration and which is received within the lowerportion of the housing 40. The blocks 51 and 52 are preferablyfabricated of an electrically insulating plastic material; and thecontacts 21, 22, 23, 26 and 27 are retained in the subassembly 41 withsuitable insulating walls and barriers insulating the contacts from eachother.

As best seen in FIGS. 1, 2 and 9, the bridging contact 20, forengagement with the stationary contacts 21, 22 and 23, and the bridgingcontact 25, for engagement with the stationary contacts 26 and 27, aremounted in side-by-side relation on the shank 46 of the actuator 45.

Referring to the contact 25, as seen in FIGS. 1 and 9, this contact isan elongated, rectangular shaped platelike member having a contact boss61 projecting from one side edge at one end thereof, and having aV-shaped notch 62 at its opposite side edge spaced from both ends. Theactuator shank 46 is generally rectangular in cross section; and oneside thereof is provided with a rectangular recess 64 opening to thebottom wall thereof and dimensioned to accommodate the contact 25. Acylindrical recess 65 in the shank opens to the downward facing base ofthe recess 64 and confines and guides a pivot pin 66 and helicalcompression spring 67, the pivot pin being aligned with and engaging thecontact notch 62 to urge the contact 25 downwardly. When the actuator isassembled in the housing 40, the actuator slot 64 and adjacent housingwall 68 confine the contact 25 for rectilinear movement with theactuator, with the contact being urged downwardly by the spring 67 intoengagement with the associated stationary contacts. It will be notedthat pin 76 is not required since notch 62 can be of a shape toexpeditiously receive the end of the spring in which event the springcould provide the dual function of pivot and biasing member.

As best seen in FIG. I, the stationary contact 26 is provided with anupwardly projecting portion 69 defining a pivot which is engaged by andsupports the downward facing edge of the bridging contact 25. The pivot69 opposes and confronts the pivot 66; and the relative lateralpositions of these pivots provide the positive switching action whichwill now be described, with particular reference to FIGS. 1,3 and 5.

In FIG. 1, the actuator 45 is shown in its most extended positionrelative to the housing 40, being urged to this position by the spring48 and being limited in an outward excursion by stop means not shown. Inthis position, the actuator pivot 66 is overcenter to the left relativeto the contact pivot 69, so that the bridging contact 25 is rotated in acounterclockwise direction relative to the pivot 69 as viewed in FIG. Ito lift and maintain the contact boss 61 out of engagement with thestationary contact 27. This is the off" position of the switch.

In FIG. 3, the actuator 45 has been moved to an intermediate positionrelative to the housing 40 wherein the actuator pivot 66 has now beenmoved overcenter to the right relative to the contact pivot 69, therebyrotating the contact 25 clockwise relative to the pivot 69 to move thecontact boss 61 into engagement with the stationary contact 27. Duringthis movement, the contact 25 slides to the right on the pivot 69maintaining electrical contact with the stationary contact 26 throughthe pivot 69. l

The FIG. 5 position represents the extreme position of the actuator 45resulting from squeezing the trigger element 47; and it will be seenthat the bridging contact 25 has slid further along the pivot 69 and thestationary contact 27 to maintain bridging electrical contact betweenthe contacts 26 and 27. When the actuator is released by the operator,the spring 48 will urge the actuator back to its FIG. 1 position todisengage the bridging contact from the stationary contact 27. Thebridging contact boss 61 engages only the contact 27, and does not comeinto engagement with the rib 57 or other parts of the subassembly block51.

Referring now particularly to FIGS. 2, 4 and 6, the adjacent bridgingcontact 20 is identical in configuration to the contact 25, including acontact boss 71 projecting from a lower edge at one end and a V-shapednotch 72 in the upper edge intermediate its ends. The contact 20 issimilarly confined in a rectangular recess 74 provided in the oppositeside of the actuator shank 46; and an upward extending cylindricalrecess 75 confines the pivot pin 76 and associated helical compressionspring 77 for engaging the notch 72 and urging the bridging contactdownwardly into engagement with the associated stationary contacts. Therecess 74 with the adjacent housing wall 78 confines the contact 20 forrectilinear movement with the actuator and for pivotal movement relativeto the stationary contacts.

As best seen in FIG. 2, the stationary contact 21 is similar inconfiguration to the contact 26 including an upwardly proj ectingportion defining a pivot 79 for engaging and supporting the lower edgeof the bridging contact 20. The pivot 79 opposes and confronts the pivot76 to control the positive switching action as will now be described.

Referring particularly to FIGS. 2, 4 and 6, FIG. 2 illustrates the off"position of the switch wherein the pivot 76 is positioned overcenter tothe right relative to the pivot 79; whereby the contact 20 is rotatedclockwise to maintain the contact boss 71 out of engagement with thestationary contact 22. FIG. 4 illustrates an intermediate position ofthe actuator responsive to the squeezing of the actuator trigger by theoperator, wherein the pivot 76 has been moved overcenter to the leftrelative to the pivot 79 to rotate the contact 20 counterclockwise andurge the contact boss 71 into engagement with the stationary contact 22.During most of the movement of the bridging contact 20, the boss 71maintains sliding engagement with the stationary contact 22 while thecontact 20 also maintains engagement with the pivot 79 of the stationarycontact 21, to maintain closed circuit through these contacts.

As seen in FIG. 11, the contact 22 is connected in series with theresistors 33 and 34.

FIG. 6 illustrates the extreme position of the actuator 45,corresponding to that of FIG. 5, wherein the boss 71 of the bridgingcontact has been moved off contact 22 and into engagement with thestationary contact 23. Again, when the actuator is released by theoperator, the bridging contact 20 will be returned to the FIG. 2position.

Throughout these switching movements, the boss 71 of bridging contact 20engages only the contacts 22 and 23, and does not engage the insulatingrib 58.

FIG. 7 is a view of one face of a thick film circuit 81 which includesprinted circuit conductors and components and which is included in thesubassembly 41. The thick film circuit consists, for example, of aceramic wafer 81 and, as seen in both FIGS. 7 and 10, it includes theresistor elements 33 and 34 and associated terminals 35 and 36 which arereferred to in connection with the circuit diagram of FIG. 11. As bestseen in FIGS. 9 and 10, the circuit wafer 81 is enclosed in a cavity 82defined between the subassembly blocks 51 and 52. The wafer is supportedagainst the block 52; and the bridging slide contact 30 is alsosupported and guided in this recess 82. As best seen in FIGS. 9 and 10,the sliding contact 30 consists of a thin waferlike plate of conductivespring metal having a lower pair of laterally extending fingers 83 whichare received in a longitudinal groove 84 formed in the wall of the block51 facing the circuit wafer 81. The coaction of the fingers 83 and thegroove 83 prevent vertical movement of the sliding contact 30 and permitlongitudinal sliding movement. The sliding contact also includeslaterally extending contact fingers 31 and 32 which are urged againstthe resistor elements 33 and 34 to provide the variable resistance inthe circuit.

The sliding contact 30 also includes an upwardly extending tab 85, bestseen in FIG. 10, which is received in a narrow elongated recess 86, bestseen in FIGS. 8 and provided in the lower wall of the actuator shank 46.The length of the recess 86 is only slightly greater than thelongitudinal dimension of the tab 85, so that the contact moveslongitudinally and rectilinearly with the actuator 45 to position thecontact fingers 31 and 32 relative to the respective resistor elements33 and 34. It will be appreciated that the particular sliding contact ismerely exemplary of many known in the art.

In FIGS. 8, 9 and 10, the parts of the switch and power control assemblyare illustrated in the off position of the switch corresponding to thatof FIGS. 1 and 2. In this position the contact fingers 31 and 32 engagethe respective resistor elements at extreme left end of these elementsas viewed in FIGS. 7 and 10. Accordingly, when the actuator is movedjust slightly away from the off position, wherein the bridging contactsand have just moved to the position to make positive engagement with therespective stationary contacts 22 and 27, the variable resistanceprovided in the circuit will be a maximum with the current flowing, forexample, from terminal 35 through the resistor element 33, the slidingcontact 30, and the resistor element 34 to the terminal 36. As thesliding contact is moved toward the right, as viewed in FIG. 10,resulting from the squeezing of the actuator trigger element 47, thelengths of the resistor elements 33 and 34 which are effective in thecircuit decreases to provide a diminishing variable resistance. When theactuator is moved to its extreme position, corresponding to that ofFIGS. 5 and 6, the bridging contact fingers 31 and 32 are in engagementwith the terminals 35 and 36 so that no current flows through theresistor elements 33 and 34. Simultaneously, as described in connectionwith FIG. 6, the bridging contact 20 engages stationary contact 23 and,as seen in FIG. 11, the motor is connected directly across line voltage.

The operation of the switch and power control, as described above, maybe briefly outlined as follows:

In the off" position of the switch, illustrated in FIGS. 1, 2, 8, 9 and10, the sliding contact is positioned to provide the maximum variableresistance in the circuit through the resistors 33 and 34. When theactuator 45 is moved slightly from the off position, the bridgingcontacts 20 and 25 are moved relative to the respective contact pivots79 and 69 so that these contacts are snapped into engagement with therespective stationary contacts 22 and 27. It is seen, with reference tothe circuit diagram of FIG. 11, that the resistor elements 33 and 34 arethen connected into the power control circuit. FIGS. 3 and 4 illustratethe condition where the bridging contacts 20 and 25 have just snappedinto engagement with the respective stationary contacts.

As the actuator is moved further by the operator, bridging contact 20continues to bridge the contacts 21 and 22 maintaining slidingengagement therewith, and bridging contact 25 continues to bridge thecontacts 26 and 27 maintaining sliding engagement therewith. The slidingcontact 30 moves across the resistor elements 33 and 34 to decrease thevariable resistance and increase the applied power to the load; or, asthe trigger is released, the resistance is increased to decrease theapplied power. In the extreme position of the actuator, power is appliedto the motor as the motor is connected directly in series with appliedline voltage.

What has been described is an improved switch and power control assemblyparticularly adapted for use with a portable electric power tool forcontrolling the speed of a series connected motor. A feature of theinvention is the provision of a positive acting switch including abridging contact which maintains continuous engagement with onestationary contact and which is snapped positively into and out ofengagement with another stationary contact. A particular feature of theswitch is that the bridging contact is urged by spring means intoengagement with the two stationary contacts, and the switching action iseffected by a pivoting movement of the bridging contact about a fixedpivot on the one stationary contact so that all of the slidingengagement is between the contact members of the switch assembly. Anancillary feature of the switch arrangement is that an insulatingbarrier or rib may be provided between the adjacent stationary contactsand yet will not be engaged or abraided by the movable bridging contact.Another feature of the invention is the provision of a variable powercontrol, which includes a positive acting switch, and a thick filmcircuits carrying integral resistor elements wiped by a sliding contactcarried with the switch actuator to provide variable resistance in thecontrol circuit.

Although the invention has been described with reference to a particularpreferred embodiment, many changes and modifications will becomeapparent to those skilled in the art in view of the foregoingdescription which is intended to be illustrative and not limiting of theinvention defined in the claims.

Iclaim: 1. An electrical switch comprising a housing; an actuatormounted for rectilinear movement relative to said housing; 7

at least two spaced stationary contacts mounted on said housing; anelongated bridging contact carried by said actuator for rectilinearmovement therewith, for selective bridging engagement with saidstationary contacts;

one of said stationary contacts defining integral contact pivot means;said bridging contact being mounted on said actuator for pivotalmovement relative to said contact pivot means; spring pivot means onsaid actuator opposing said stationary contact pivot means andcontinuously urging-said bridging contact toward the stationarycontacts;

said bridging contact being movable between a nonbridging position,wherein said bridging contact is positioned relative to said pivot meansto affect rotation of the contact out of engagement with the other ofsaid stationary contacts, and the bridging position wherein saidbridging contact is positioned relative to said pivot means to effectrotation of the contact into engagement with the other stationarycontact,

said elongated bridging contact having one end disposed for continuoussliding engagement with said contact pivot means, and having a boss atits other end for selective engagement with said other stationarycontact;

said housing providing a transverse insulating boss between said spacedstationary contacts; and said bridging contact being maintained out ofengagement with said insulating boss in all positions thereof. 2. Anelectric switch as set forth in claim 1 wherein said housing is adaptedto be mounted in a pistol grip handle of a control device; wherein saidactuator includes an integral trigger projecting from said housing andadapted to be engaged by the finger of an operator; and means urgingsaid actuator to an extended position wherein said bridging contact ispositioned in the nonbridging position. 3. An electric switch as setforth in claim 1 wherein said stationary contacts are disposed generallyin a plane parallel to the direction of rectilinear movement;

said bridging contact being confined in a recess in said actuator forpivotal movement in a plane perpendicular to the plane of saidstationary contacts; said actuator a spring pivot means comprising anelongated coil spring guided in a hole in said actuator transverse tosaid stationary contact plane biasing said bridging contact intermediateits ends.

4. An electric switch as defined in claim 3 wherein said pivot meansfurther include an elongated pin guided in said hole and urged by saidspring into engagement with said bridging contact intermediate its ends.

5. An electric switch as set forth in claim 1 including at least fourstationary contacts mounted on said housing and disposed generally in aplane parallel to the direction of rectilinear movement; said stationarycontacts comprising first and second longitudinally spaced contacts andthird and fourth longitudinally spaced contacts disposed in side-by-siderelation;

first and second bridging contacts mounted on said actuator inside-by-side relation for rectilinear movement therewith; said firstbridging contact being disposed for selective bridging engagement withsaid first and second stationary contacts, and said second bridgingcontact being disposed for selective bridging engagement with said thirdand fourth stationary contacts;

each of said first and third stationary contact having integral pivotmeans engaged by said bridging contacts; members; and spring pivot meanson said actuator urging each of said bridging contacts into engagementwith the respective stationary contacts.

6. An electric switch as set forth in claim a including three stationarycontacts mounted on said housing in longitudinally spaced relation anddisposed generally in a plane parallel to the direction of rectilinearmovement; said bridging contact being maintained in continuousengagement with said one contact pivot means; and said boss of saidbridging contact selectively engaging one of the other two stationarycontacts responsive to the amount of rectilinear movement of saidbridging contact from the new bridging position.

7. An electric switch and power control comprising a housing; anactuator mounted for rectilinear movement relative to said housing;

at least two spaced stationary contacts mounted on said housing; anelongated bridging contact carried by said actuator for rectilinearmovement therewith; for selective bridging engagement with saidstationary contacts;

one of said stationary contacts defining integral contact pivot meanssaid bridging contact being mounted on said actuator for pivotalmovement relative to said contact pivot means; spring pivot means onsaid actuator opposing said stationary contact pivot means andcontinuously urging said bridging contact toward the stationarycontacts; and

said bridging contact being movable between a nonbridging position,wherein said bridging contact is positioned relative to said pivot meansto affect rotation of the contact out of engagement with the other ofsaid stationary contacts, and the bridging position, wherein saidbridging contact is positioned relative to said pivot means to effectrotation of the contact into engagement with the other stationarycontact;

said elongated bridging contact having one end disposed for continuoussliding engagement with said contact pivot means, and having a boss atits other end for selective engagement with said other stationarycontact; said housing providing a transverse insulating boss betweensaid spaced stationary contacts; and said bridging contact beingmaintained out of engagement with said insulating boss in all positionsthereof; power control circuit means including elongated resistor meansmounted on said housing; a second contact movable rectilinearly withsaid actuator, having slide means engaging said resistor means and beingmovable through selective positions along said resistor means to providea plurality of resistance values; and means electrically connecting saidresistor means with one of said stationary contacts. 8. An electronicswitch and power control as set forth in claim 10 wherein saidstationary contacts are disposed generally in a plane parallel to adirection of rectilinear movement; said bridging contact being confinedin a recess in said actuator for pivotal movement in a planeperpendicular to the plane of said stationary contacts; said springpivot means comprising an elongated pin guided in a hole in saidactuator transverse to said stationary contact plane and spring meansurging said pivot pin into engagement with said bridging contactintermediate its ends. 35 9. An electric switch and power control as setforth in claim including guide means on said housing for supporting andguiding the rectilinear movement of said second movable contact; andsaid second movable contact and said actuator having respective coatingtab and recess means for effecting the rectilinear movement of saidcontact with said actuator. 10. An electric switch and power control asset forth in claim 7 wherein said resistor means comprises a pair ofelongated resistor elements aligned and spaced longitudinally in adirection parallel to the direction of rectilinear movement; one end ofeach of said resistor elements being connected in said power controlcircuit means; and wherein said second movable contact comprises abridging contact having a pair of slide fingers for engagement with therespective resistor elements, defining a series connection between saidresistor elements. 55 11. An electric switch and power control as setforth in claim 7 including a thick film printed circuit mounted on saidhousing; said resistor means being provided by an elongated resistorelement formed on a surface of said thick film circuit. 12. Anelectronic switch and power control as set forth in claim 11 whereinsaid housing defines a cavity for confining said thick film circuit; andwherein said actuator is provided with a recess for accommodating aprojecting boss of said second movable contact whereby said contact ismoved rectilinearly with said actuator. 13. An electric switch and powercontrol as set forth in claim 11 wherein said thick film circuit isprovided with a pair of elongated resistor elements arranged on thesurface thereof in longitudinal alignment; and wherein said secondmovable contact is provided with a pair of contact fingers each engagingone of said resistor elements, defining a series connection between saidresistor elements.

1. An electrical switch comprising a housing; an actuator mounted forrectilinear movement relative to said housing; at least two spacedstationary contacts mounted on said housing; an elongated bridgingcontact carried by said actuator for rectilinear movement therewith, forselective bridging engagement with said stationary contacts; one of saidstationary contacts defining integral contact pivot means; said bridgingcontact being mounted on said actuator for pivotal movement relative tosaid contact pivot means; spring pivot means on said actuator opposingsaid stationary contact pivot means and continuously urging saidbridging contact toward the stationary contacts; said bridging contactbeing movable between a nonbridging position, wherein said bridgingcontact is positioned relative to said pivot means to affect rotation ofthe contact out of engagement with the other of said stationarycontacts, and the bridging position wherein said bridging contact ispositioned relative to said pivot means to effect rotation of thecontact into engagement with the other stationary contact, saidelongated bridging contact having one end disposed for continuoussliding engagement with said contact pivot means, and having a boss atits other end for selective engagement with said other stationarycontact; said housing providing a transverse insulating boss betweensaid spaced stationary contacts; and said bridging contact beingmaintained out of engagement with said insulating boss in all positionsthereof.
 2. An electric switch as set forth in claim 1 wherein saidhousing is adapted to be mounted in a pistol grip handle of a controldevice; wherein said actuator includes an integral trigger projectingfrom said housing and adapted to be engaged by the finger of anoperator; and means urging said actuator to an extended position whereinsaid bridging contact is positioned in the nonbridging position.
 3. Anelectric switch as set forth in claim 1 wherein said stationary contactsare disposed generally in a plane parallel to the direction ofrectilinear movement; said bridging contact being confined in a recessin said actuator for pivotal movement in a plane perpendicular to theplane of said stationary contacts; said actuator a spring pivot meanscomprising an elongated coil spring guided in a hole in said actuatortransverse to said stationary contact plane biasing said bridgingcontact intermediate its ends.
 4. An electric switch as defined in claim3 wherein said pivot means further include an elongated pin guided insaid hole and urged by said spring into engagement with said bridgingcontact intermediate its ends.
 5. An electric switch as set forth inclaim 1 including at least four stationary contacts mounted on saidhousing and disposed generally in a plane parallel to the direction ofrectilinear movement; said stationary contacts comprising First andsecond longitudinally spaced contacts and third and fourthlongitudinally spaced contacts disposed in side-by-side relation; firstand second bridging contacts mounted on said actuator in side-by-siderelation for rectilinear movement therewith; said first bridging contactbeing disposed for selective bridging engagement with said first andsecond stationary contacts, and said second bridging contact beingdisposed for selective bridging engagement with said third and fourthstationary contacts; each of said first and third stationary contacthaving integral pivot means engaged by said bridging contacts; members;and spring pivot means on said actuator urging each of said bridgingcontacts into engagement with the respective stationary contacts.
 6. Anelectric switch as set forth in claim a including three stationarycontacts mounted on said housing in longitudinally spaced relation anddisposed generally in a plane parallel to the direction of rectilinearmovement; said bridging contact being maintained in continuousengagement with said one contact pivot means; and said boss of saidbridging contact selectively engaging one of the other two stationarycontacts responsive to the amount of rectilinear movement of saidbridging contact from the new bridging position.
 7. An electric switchand power control comprising a housing; an actuator mounted forrectilinear movement relative to said housing; at least two spacedstationary contacts mounted on said housing; an elongated bridgingcontact carried by said actuator for rectilinear movement therewith; forselective bridging engagement with said stationary contacts; one of saidstationary contacts defining integral contact pivot means said bridgingcontact being mounted on said actuator for pivotal movement relative tosaid contact pivot means; spring pivot means on said actuator opposingsaid stationary contact pivot means and continuously urging saidbridging contact toward the stationary contacts; and said bridgingcontact being movable between a nonbridging position, wherein saidbridging contact is positioned relative to said pivot means to affectrotation of the contact out of engagement with the other of saidstationary contacts, and the bridging position, wherein said bridgingcontact is positioned relative to said pivot means to effect rotation ofthe contact into engagement with the other stationary contact; saidelongated bridging contact having one end disposed for continuoussliding engagement with said contact pivot means, and having a boss atits other end for selective engagement with said other stationarycontact; said housing providing a transverse insulating boss betweensaid spaced stationary contacts; and said bridging contact beingmaintained out of engagement with said insulating boss in all positionsthereof; power control circuit means including elongated resistor meansmounted on said housing; a second contact movable rectilinearly withsaid actuator, having slide means engaging said resistor means and beingmovable through selective positions along said resistor means to providea plurality of resistance values; and means electrically connecting saidresistor means with one of said stationary contacts.
 8. An electronicswitch and power control as set forth in claim 10 wherein saidstationary contacts are disposed generally in a plane parallel to adirection of rectilinear movement; said bridging contact being confinedin a recess in said actuator for pivotal movement in a planeperpendicular to the plane of said stationary contacts; said springpivot means comprising an elongated pin guided in a hole in saidactuator transverse to said stationary contact plane and spring meansurging said pivot pin into engagement with said bridging contactintermediate its ends.
 9. An electric switch and power control as setforth in claim 7 including guide means on said housing for supportingand guiding the rectilinear movement oF said second movable contact; andsaid second movable contact and said actuator having respective coatingtab and recess means for effecting the rectilinear movement of saidcontact with said actuator.
 10. An electric switch and power control asset forth in claim 7 wherein said resistor means comprises a pair ofelongated resistor elements aligned and spaced longitudinally in adirection parallel to the direction of rectilinear movement; one end ofeach of said resistor elements being connected in said power controlcircuit means; and wherein said second movable contact comprises abridging contact having a pair of slide fingers for engagement with therespective resistor elements, defining a series connection between saidresistor elements.
 11. An electric switch and power control as set forthin claim 7 including a thick film printed circuit mounted on saidhousing; said resistor means being provided by an elongated resistorelement formed on a surface of said thick film circuit.
 12. Anelectronic switch and power control as set forth in claim 11 whereinsaid housing defines a cavity for confining said thick film circuit; andwherein said actuator is provided with a recess for accommodating aprojecting boss of said second movable contact whereby said contact ismoved rectilinearly with said actuator.
 13. An electric switch and powercontrol as set forth in claim 11 wherein said thick film circuit isprovided with a pair of elongated resistor elements arranged on thesurface thereof in longitudinal alignment; and wherein said secondmovable contact is provided with a pair of contact fingers each engagingone of said resistor elements, defining a series connection between saidresistor elements.